Rates of Sulfate Reduction and Iron Reduction in the Sediment Associated with Abalone Aquaculture in the Southern Coastal Waters of Korea

Abstract

: We investigated geochemical properties, and microbial sulfate-and iron(III) reduction in sediment influenced by the aquaculture of abalone in the Nohwa-do, southern coastal sea in Korea. Concentrations of ammonium, phosphate, and sulfide in the pore-water were higher at farm sites than at control sites. The differences between the 2 types of sites were most apparent in terms of the weights of abalone and the temperature increase during September. Accordingly, the rates of sulfate reduction at the farm sites during September (61 mmol S m) were 3-fold higher than the sulfate reduction during May (20 mmol S m). In contrast, Fe(III) reduction rates were highest at the control sites in May, but its significance was relatively decreased at farm sites during September when sulfate reduction rates were highest. During September, benthic ammonium flux was 3-fold greater at the farm sites (35 mmol N m ). Overall results indicated that the inappropriate operation of a large-scale aquaculture farm may result in excess input of biodeposits and high nutrient fluxes from the sediment, thereby decreasing diversity of the benthic ecosystem and deepening eutrophication in coastal waters.

Eutrophication Driven by Aquaculture Fish Farms Controls Phytoplankton and Dinoflagellate Cyst Abundance in the Southern Coastal Waters of Korea

“…Nutrients introduced from land via runoff contribute to high primary productivity in coastal waters, but excessive nutrient input exacerbates water quality and often causes harmful algal blooms [25,26]. Massive aquaculture farms are located along the southern coast of Korea; thus, organic matter originating from terrestrial regions and an excessive supply of food aggravate pollution around the aquaculture farms [27,28]. Typically, 40% of organic matter that flux into coastal sediments is degraded at the benthic boundary layer and 60% is buried in the aquaculture farm sediments [29].…”